Enhanced gain and miniaturisation method of stacked dielectric resonator antenna using metallic cap

The authors introduce a miniature and gain enhancement method of dielectric resonator antenna (DRA) using a metallic cap. The structure of the proposed antenna consists of a stacked cylindrical dielectric resonator, a metallic cap that is located on the resonator, and a ground plane. By adjusting the size of the metallic cap while retaining the size of the antenna, the proposed antenna operates in the lower frequency band and shows improved realised gain. As the radius of metallic cap increases, wavelength at z-axis increases and the resonance frequency gets lower. In addition, tangential field at side wall surface increases, which leads to the enhancement of realised gain at resonance frequency. The authors have fabricated a prototype of the antenna for the experimental verification. The simulation results are in a close agreement with the experimental finding.